Wonder Soil wafers are made from a compressed premium coco coir mix. Expanding Potting Soil Wafers are made with nutrients, mycorrhizae, kelp, worm castings, and unique water-saving polymers. Wafers are easy to carry, easy to use, and easy to grow. The wafers expand when re-hydrated with water. Water usage is reduced by up to 50%, while promoting amazing gardening success. Choose either a 1 3/16", 2" or 3" wafer.